초록 ▼

Alkali-free glasses are disclosed which can be used to produce substrates for flat panel display devices, e.g., active matrix liquid crystal displays (AMLCDs). The glasses contain iron and tin as fining agents, and preferably are substantially free of arsenic and antimony. In certain embodiments, th

Alkali-free glasses are disclosed which can be used to produce substrates for flat panel display devices, e.g., active matrix liquid crystal displays (AMLCDs). The glasses contain iron and tin as fining agents, and preferably are substantially free of arsenic and antimony. In certain embodiments, the glasses are also substantially free of barium. Methods for producing alkali-free glass sheets using a downdraw process (e.g., a fusion process) are also disclosed.

대표청구항 ▼

What is claimed is: 1. A glass that is substantially free of alkali metals comprising in mole percent on an oxide basis: SiO2: 64.0-71.0 Al2O3: 9.0-12.0 B2O3: 7.0-12.0 MgO: 1.0-3.0 CaO: 6.0-11.5 SrO: 0-2.3 BaO: 0-2.3 As2O3: 0-0.05 Sb2O3: 0-0.05

What is claimed is: 1. A glass that is substantially free of alkali metals comprising in mole percent on an oxide basis: SiO2: 64.0-71.0 Al2O3: 9.0-12.0 B2O3: 7.0-12.0 MgO: 1.0-3.0 CaO: 6.0-11.5 SrO: 0-2.3 BaO: 0-2.3 As2O3: 0-0.05 Sb2O3: 0-0.05 wherein: (a) the glass has an iron content expressed as Fe2O3 in the range of 0.010-0.033 mole percent; and (b) the glass has a tin content expressed as SnO2 in the range of 0.017-0.112 mole percent. 2. The glass of claim 1 wherein on an oxide basis, SrO is at most 1.0 mole percent. 3. The glass of claim 1 wherein on an oxide basis, BaO is at most 0.1 mole percent. 4. The glass of claim 1 wherein the iron content expressed as Fe2O3 is in the range of 0.012-0.024 mole percent. 5. The glass of claim 1 wherein the tin content expressed as SnO2 is in the range of 0.021-0.107 mole percent. 6. A glass that is substantially free of alkali metals and comprises in mole percent on an oxide basis: SiO2: 64.0-71.0 Al2O3: 9.0-12.0 B2O3: 7.0-12.0 MgO: 1.0-3.0 CaO: 6.0-11.5 SrO: 0-2.3 BaO: 0-0.1 As2O3: 0-0.05 Sb2O3: 0-0.05 (a) iron expressed as Fe2O3 in the range of 0.010-0.033 mole percent; and (b) tin expressed as SnO2 in the range of 0.017-0.112 mole percent. 7. The glass of claim 1 or 6 wherein the glass satisfies the following relationship: Σ[RO]/[Al2O3]≧1.00, where [Al2O3] is the mole percent of Al2O3 and Σ[RO] equals the sum of the mole percents of MgO, CaO, SrO, and BaO. 8. The glass of claim 7 wherein the glass also satisfies the relationship: Σ[RO]/[Al2O3]≧1.25. 9. The glass of claim 1 or 6 wherein the glass has one or both of the following properties: (a) a sulfur content expressed as elemental sulfur that is less than or equal to 0.002 mole percent; and/or (b) a halide content that is less than or equal to 0.4 mole percent. 10. The glass of claim 9 wherein the glass has both properties (a) and (b). 11. The glass of claim 1 or 6 wherein the glass has one or more of the following properties: (a) a density that is less than or equal to 2.41 grams/cm3; (b) a liquidus viscosity that is greater than or equal to 100,000 poise; (c) a strain point that is greater than or equal to 650° C.; and/or (d) a linear coefficient of thermal expansion (CTE) over the temperature range 0-300° C. which satisfies the relationship: 28×10-7/° C.≧CTE≧35 ×10-7/° C. 12. The glass of claim 11 wherein the glass has all of properties (a), (b), (c), and (d). 13. The glass of claim 1 or 6 wherein the glass has an Fe2+ to Fe3+ ratio that is equal to or greater than 0.5.